Maternal depression is a common mental health problem that compromises children's development. Younger children may be especially vulnerable because of their dependence upon the mother, Toddlerhood is a crucial period for developing feelings of competence and ideas about the self. Difficulties in these areas are associated with depression in adults and older children. Thus, impaired development of self-concept and motivation may predispose the child to later depression, The proposed study tests the hypothesis that development of self-efficacy and mastery motivation are impaired in toddlers of clinically depressed mothers. Using a short-term longitudinal design, we will compare three groups of toddlers who differ in exposure to maternal depression. The first group of toddlers will have mothers who are currently depressed. The second group will have mothers who were depressed during infancy but have been remitted from depression for at least 6 months. The third group will have mothers who have never been depressed. Maternal depression status will be determined by diagnostic interview and self-report. Dyads will be assessed initially at 18 months and subsequently at 25 and 32 months. Toddlers' self-efficacy, mastery motivation, self-concept, and cognitive level will be assessed at each age. In addition, mothers' depression status, perceptions of her toddler, and interactional style with her toddler will be assessed at each age. Other potential mediating factors will also be assessed. The major aims of the study are to examine: 1) whether exposure to maternal depression affects development of self-efficacy and mastery motivation in toddlers, 2) whether these effects continue even when mothers' depression remits, 3) whether timing of exposure to maternal depression is important, and 4) whether maternal perceptions and interactional style mediate the effect of maternal depression. This research will identify deficits in the cognitive-motivational style of toddlers of depressed mothers. These cognitive-motivational deficits are important in their own right and may be precursors of depression. Results of this study will have implications for interventions to ameliorate the effects of maternal depression on children.